Shifting device for stepped gear drives



pt-29,1942- w.MoB1us Em 2,291,422

SHIFTING DEVICE FOR STEPPED GEAR DRIVES Fi1ed Dec. 26, 1939- 4 Sheets-She et 1 I H E3 ,6

B F: I

,Evenibr-s.

Sept. 29, 1942. w. MOBIUS Em 2,297,422

SHIFTING, DEVICE FOR STEPPED GEAR DRIVES Filed Dec. 26, 1939 4 Sheecs-Sheet s az x 36 j 2 venfirs.

142/ M0225. flan: flan/73M Haws [Ma /ch.

p 9 2- w. MOBIUS ErAL 2,297,422

SHIFTING DEVICE FOR STEPPED GEAR DRIVES Filed Dec. 26, 1939 4 Sheets-Shae? 4 Patented Sept. 29, 1942 SHIFTING DEVICE FOR. STEPPED GEAR DRIVES Walter Miibius, Hans Hautsch, and Hans Ulbrich, Magdeburg, Germany; vested in the Alien Property Custodian Application December 26, 1939, Serial No. 311,048 In Germany December 24, 1938 3 Claims. (01. 74-348) Granted This invention relates to stepped gear drives operated with a certain drive speed and provided,

with a number of drive steps, which permit the selection of a corresponding number of different delivered speeds. In many cases the gradation of the operating speed is also employed on power engine plants as well as onworking machines,

such as machine tools, which may be provided with such multi-stepped change speed gearing inserted between the main drive shaft and the operating shaft. Previously, the shifting to a different speed of such a gear drive was accomplished with the aid of a swinging member carrying a gear, which was in continuous engagement with the drive shaft and which was manually brought into engagement with the selected gear of-the stepped gear drive by a swinging movement and displacement of the swinging member. The operator needs both hands to handle such a swinging member thus making its operation very impracticable. In addition, a stepped gear drive of such a. construction cannot be arranged in a completely closed housing.

The purpose of the invention is, to arrange the shifting means of the drive in such a manner,

that the disadvantages of the former constructions will be eliminated. The invention is based on the idea to direct in two directions the motions of a swinging member carrying a gear which connects the drive shaft and the operating shaft, whereby the actual swing motion is directed into the direction of the drive shaft or the operating shaft and a. second motion is directed into a displacement rectangular to the aforesaid motion;

this displacement being utilized to bring the gear in engagement with the selected gear of the stepped gear drive. According 'to the invention separate drive members are provided for the two motions, however both drive members are operated by a single shift member, wherebythe shift member likewise is capable of several motions, i. e. an oscillatory motion and a rotary motion. According to the invention drive means for the oscillation and-drive means for the displacement of the swing member are provided, said means acting upon said swing member, which supports the transmission gear; both groups of said drive means are actuated by a single shift member. This makes it possible to shift in a simple manner to any of the different gear drive steps. According to the invention the entire gear drive can be arranged in a completely closed housing, which protects the running parts against the intrusion of foreign matter, particularly metal chips, and in addition the entire arrangement of under the provisions of sec. 14, act of March 2, 1927; 357 O. G. 5)

moving parts can run in an oil bath. Instead of an oil bath the mechanism may be lubricated in any other suitable manner.

Another object of the invention is the insertion ofa special drive, which imparts an additional oscillatory motion to the swinging member carrying the transmission gear, during its longitudinal displacement; the extent of this motion corresponds to the difference of distance between the pitch circles of the gear steps, depending upon the form of the steps of the gear drive unit. The shift member of the mechanism is connected with the rotary part of a worm drive or a similar cycloidal drive, the axial part of which is an element of the oscillatory drive of the swinging member. The pitch of the worm drive or the cycloidal drive is such that the shift member oscillates in one plane during the longitudinal displacement of the swing member. The part of the oscillatory drive which moves in an axial direction is connected with the shift member by a threaded sleeve, which connects the shift member with the oscillatory drive during the engaging and disengaging motion of the swing member.

This additional drive, which may consist of a sliding pin drive or a similar motion-transmitting arrangement, makes it possible that the oscillatory motions of the hand lever take place in one plane. The automatic locking of the additional shift drive and the securing of the shift lever in its rest support prevents the transmission gear of being forced out of its position by the pressure of the gear teeth in the wrong direction. Furthermore the inventionincludes some construction details of this novel shifting device which are pointed out in the following description.

Another object of the invention is to construct the shifting device so that the shifting motion during the operation of the gear drive will be simplified and uniform. According to the invention this is accomplished in that the shift member, which imparts an additional oscillatory motion to the swing member is pivotally connected with the member of the mechanism, which displaces the swing member in a. longitudinal direction. This shift member consists of two movably connected parts, one of which carries the hand lever and locking means; during the swing part of the mechanism that causes an additional oscillatory motion; an energy storer is inserted between both parts tending to hold the locking means in'its engagingposition. The object of this construction'according to the invention is, that only one swing motion is needed during the shifting of the hand lever of the gear drive, whereby this motion causes the unlocking of the locking means and following the oscillatory displacement of the swing member carrying the transmission gear. The swing motion of the hand lever is followed by a rotary movement of the lever in a direction rectangular to the first motion and causes a longitudinal displacement of the swing member. Only a swing motion and a rotary motion with the hand lever is necessary during the shifting of the gear drive thus simplifying considerably the shifting manipulations In order to fully illustrate the invention there are, by way of example, three embodiments pointed out in the present application and shown on the drawings in which:

Fig. 1 is a central vertical cross-section of one embodiment of the device.

. Fig. 2 is a section on line IIII of Fig. 1 showing the different parts in a certain position.

Fig. 3 is a similar view. as Fig. 2 showing the difierent parts in another position.

Fig. 4 is a view partly in section taken on the broken line IVIV of Fig. 2.

Fig. 5 shows a cross-section of the second embodiment.

Fig. 6 is an elevational view of the hand lever arrangement.

Fig. 7 is another elevational view of the hand lever arrangement.

Fig. 8 shows a longitudinal central vertical cross-section of another embodiment.

As shown on the drawings the shaft I shall illustrate the main drive shaft of a lathe. A part of the shaft is to a certain length provided with gear teeth 2. An oscillating frame 3 is arranged on a sleeve 6 surrounding the shaft I. This swing frame 3 supports a gear 4 which is in engagement with the gear teeth 2 of the shaft I about which this frame 3 may swing. The gear 4 is provided for engagement with any one of gears of a. cone gear arrangement, a socalled Norton block. The swing frame 3 can be displaced on the sleeve in a longitudinal direction but cannot turn about this sleeve; therefore the swing member. 3 is capable of oscillatory movement about the axis of the shaft I and longitudinal displacement with respect to said shaft.

The sleeve 6 carries a gear segment I which engages the gear teeth 8 provided on a push rod 9. The sleeve 6 has a window I0 (Figs. 2 and 3) which is arranged in such a manner that the gear 4 is able to engage the gear teeth 2 of the shaft I. The push rod 9 is supported by a sleeve II, which is arranged in and extending over the bore of a boss of the housing I2 which encloses the entire gear drive; the push rod 3 is capable of being displaced in a longitudinal direction within the sleeve I I, while the sleeve II is able to turn about its axis. The outer end of the sleeve II has a handle-like shape and supports a shift member in the form of a hand lever I3. The lower ball-shaped end of the lever I3 engages a slot I4 of the push rod 9. If the lever I3 is swung as indicated in Figs. 2 and 3 the push rod 9 is displaced within the sleeve II causing the swing frame 3 to be oscillated by means of the engagement between gear teeth I with the gear segment 3, whereby the gear 4 is either engaged withor disengaged from one of the gear steps of the cone gear 5 as the case may The engagement of the gears is influenced by a spring l5 (Fig. 2) one end ofwhich is connected to the sleeve 6 and the other end with the housing I2. The correct approach of the pitch circle of the gear 4 to the pitch circle of the selected gear step of the cone gear 5 is assured in that an abutment plate I6 of the swing frame 3 abuts an adjustable pin I'I arranged in the housing. The number of the pins I1 corresponds with the number of gear steps of the cone gear 5 and the position of the pins with respect to the swing axis depends upon the diameter of the pitch circle of the different steps (see Fig. 4).

A gear I8 is fixedly secured to the sleeve I I and engages a slidable rack I9 provided in the housing. The rack IS-carries a fork 20 (Fig. 1) which engages an extension 2| of the swing frame 3. If the hand lever I3 is turned (compare Fig. l) the motion will be transmitted by the sleeve II, the gear l8 to the rack I9, from there to the fork 20 and the swing frame 3 which will be longitudinally displaced.

The circumference of the handle-like end of sleeve II is provided with a number of indentations 22', which correspond in number and in the distances from each other to the different steps of the cone gear 5. The indentations 22 receive the spring-pressed ball 23, which takes care, that during the turning of the lever I3 and the sleeve II the latter as well as all the other parts to which the movement of the sleeve is transmitted are positioned in such a manner that during the shifting process the gear 4 is longitudinally exactly opposite the selected gear step of the gear cone 5. The correct position of the lever I3 for every step of the gear drive can be read off on circularly arranged markings 24 provided concentric to the sleeve I I on the outside of housing (Figs. 2 and 3). The housing I2 is completely closed; the sleeve II is arranged in the bore of the housing wall with sufficient tightness to avoid leakage of lubricant and prevent dirt from'entering. The shift lever I3 is supported in the sleeve II by means of a ball 25 which provides the lever with the required movability and forms a completely leak-proof sealing element.

In the embodiment of Figs. 5 to 7 the lever 3I (Fig. 5) is arranged in a guide sleeve 32 and may move in an axial direction; a spring 33 urges the lever downward and keeps its lowermost end 34 in notches 35, which are circularly arranged on the circumferential surface of a sleeve 31 fixed to the machine frame 36, By lifting the lever 3| in the direction of the arrow :1: its lower end 34 is removed from the notch and the lever can be moved in the direction of the arrow 1 whereby a lever 38 fixedly secured to the sleeve 32 turns a gear 39, which moves the rack 40 in a transverse direction. A threaded sleeve 4| is rigidly connected with the rack 40 and engages a threaded member 42; this threaded member 42 is integral with a rack 43 which follows the movements of the rack 40. The rack 43 engages a toothed part of the swing member 44 shown on the drawing in dotted lines; the swing member .44 can turn about a shaft 45 and the transmitting gear 46 carried by the swing member 44 may oscillate about this shaft 45 and may be brought in and out of engagement with the gears 41 of the cone gear.

If the hand lever 3| is moved in the direction of the arrow 2 (Fig. '7) the lever 38 moves also and turns the sleeve 48. A gear 49 is secured to the sleeve 48 (Fig. and engages a rack 56 which is moved in a longitudinal direction by said gear. The rack 50 moves the swing member 44 by means of a fork 5| (shown in dotted lines) and consequently the gear 46 until it opposes the setends from the underside of the extension 12 downward and is slightly conical. Within the lected gear step. The motion of the hand lever 3| in the direction of the arrow 2 (Fig. 7) causes a simultaneous rotary motion of the threaded sleeve 4| with regard to the spindle 42; as the rack 43 by virtue of his engagement with the gear 45 prevents the spindle 42 from turning an additional longitudinal displacement of the rack 43 takes place and consequently an additional oscillatory motion of the swing member 44, so that the transmitting gear 46 remains in close proximity of the gear step of the cone gear, this position corresponds to the notch 35 (Fig. 6) into which the lever 3| shall be inserted.

As soon as the hand lever 3| (Fig. 5) is returned in its vertical position and is inserted into a certain notch 35, the actual oscillatory motion is simultaneously imparted to the swing member 44 by means of the rack 43, the threaded connection 4|, 42', the rack 40 and the gear 39, thus bringing the transmitting gear 46 in engagement with the selected gear cone for which this notch 35 is provided.

This new shifting device adds to the motion of the hand lever 3|, which causes a lateral displacement of the transmitting gear 46 alongside the cone gear unit a second motion which is brought forth by the action of the screw drive 4|, 42; the purpose of this second motion is to adjust the position of the transmitting gear 46 to the different steps of the cone gear, so that the transmitting gear remains always in close proximity of the cone gear unit.

In the embodiment of Figs. 5 to 7 it was assumed that the diameters of the difierent pitch circles decrease uniformly, so that all engagement positions of the gear 46 fall on a straight line and accordingly the drive 4| 42 which causes the additional motion can be a screw drive. i. e. a drive with a uniform pitch. In other cases the helical line of the drive 4|, 42 must be substituted by a curve with its pitch changing in a manner corresponding to the curved line on which the engaging positions of the .gear 46 with the gear steps are located. In both cases, the notches 35 for the shift lever 4| remain in the same plane which advantageously is arranged vertically to the axis of the sleeve 48. The advantages of such an arrangement are the simplified manufacture of the sleeve 48 with the notches and that the operator can locate the notches much easier. Another embodiment of the invention is shown on the drawing in Fig. 8 and described as foll: ws: The gear drive housing 6| supports a sleeve 62 which can rotate about its axis; a shift member 63 movable in a longitudinal direction is provided within said sleeve and'this shift member imparts over a rack and a gear an oscillatory moti m to a swing member carrying a transmitting gear. these parts are not shown on the drawing. The outer end of the movable shift member 63 carries a rack 64 which is in engagement with a gear segment 65 of a lever 66, pivotally mounted on a bolt 61 in the housing 6|. In the upper forkshaped part 68 of the lever 66 is a lever 10 pivotally mounted on a bolt 69 and integral with the hand lever II. The extension 12 of lever '10 carries a lock bolt 13 the lower end of which exoperating range of the lock bolt 13 a number of conical apertures 15 are provided in a sleeve 14 connected with the housing 6|; the number and the positions of the apertures correspond with the different steps of the stepped gear drive. The lever 10 has a slanting surface 11 opposite the upper surface 16 of the lever 66,'both surfaces form together an acute angle ofa certain size. The lever 10 is provided with a bore 79 for a spring 80 which presses against the surface 16 of the lever 66.

If the shift lever is in a position as shown on the drawing in full lines the locking bolt 13 engages one of the notches 15. The tension of the spring holds the bolt 13 and the lever 10 in this position. When the speed of the operating shaft of the drive shall be changed by shifting the a the surfaces 16 and 11 abut each other. Thereby the spring 80 is pressed together, the locking Y bolt 13 is removed from the aperture and the locking of the existing shift position is ended. If the hand lever II is moved further in the direction ofthe arrow at the slidable member 63 is displaced in a longitudinal direction and causes an oscillatory motion of the swing member carrying the transmitting gear while the longitudinal displacement of this swing member is accomplished by moving the hand lever in a direction transverse to the plane of the drawing.

We claim:

1. A gear shift mechanism for machine tools comprising a driving shaft, a stepped gear connected to a driven shaft, a transmitting gear shifting rod, a shifting lever, means connecting said lever to said rod for longitudinally displacing said rod upon movement of said lever in a first direction and for rotating said rod upon movement of said lever in a second direction. and gear means joining said rod to said mounting means for initially gyrating said gear mounting means upon movement of said lever in said first direction and then further gyrating and simultaneously moving said mounting means longitudinally of said driving shaft upon movement of said lever in said second direction.

2. A gear shifting mechanism as in claim 1, further comprising means for selectively locking saidlever in positions corresponding to the position of said transmitting gear when engaged with said stepped gear.

3. A gear shifting mechanism as in claim 1, further comprising means for selectively locking said lever in positions corresponding to the position of said transmitting gear when engaged with said stepped gear, and said means connecting said lever to said rod comprising means for moving said rod longitudinally upon operation of said locking means.

WALTER MCSBIUS. HANS HAUTSCH. HANS ULBRICH. 

